The Impact of Genetically Engineered Crops on Farm Sustainability in the United States

Public Briefing

NAS Lecture Room

April 13, 2010

David E. Ervin (chair), Portland State UniversityYves Carrière, University of ArizonaWilliam J. Cox, Cornell UniversityJorge Fernandez-Cornejo, USDA-Economic Research ServiceRaymond A. Jussaume, Washington State UniversityMichele C. Marra, North Carolina State UniversityMicheal D.K. Owen, Iowa State UniversityPeter H. Raven*, Missouri Botanical GardenL. LaReesa Wolfenbarger, University of Nebraska, OmahaDavid Zilberman, University of California, Berkeley

*Members of the National Academy of Sciences

Study Committee Members

• Study the environmental, economic, and social impacts of genetically engineered (GE) crops on U.S. farms

• Identify gaps and future applications of genetic engineering technology

• Funded by the National Research Council

Purpose of the Study

• Retrospective examination (1996-today)

• Geographically restricted to the United States

• Effects on farms with and without GE-crop production

Genetic Engineering Technology

3 Types of Resistance

• Herbicide Resistance (HR)

– Most U.S. crops engineered with resistance to glyphosate

• Insect Resistance (IR)

– Types of soil bacterium (Bacillus thuringiensis) introduced into plant to target susceptible insects

• Virus Resistance

Genetically Engineering Crops

0

20

40

60

80

100

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Year

Per

cent

GE

cro

ps

All GE Corn Varieties

All GE Cotton Varieties

All GE Soybean Varieties

Nationwide acreage of GE soybean, corn, and cotton as a percentage of all acreage of these crops

Source: USDA-NASS (2001, 2003, 2005, 2007, 2009b).

GE Crops Analyzed in the Report

• Soybeans– Herbicide resistance

• Corn– Herbicide resistance – Insect resistance

• Cotton– Herbicide resistance– Insect resistance

Environmental Effects

• Complementary adoption of HR crops and conservation tillage practices

– Improves soil retention

–Probable improvement in surface water quality

– Infrastructure needed to track water quality effects

Herbicide-Resistant CropsTrends in conservation tillage practices

Source: CTIC, 2009; USDA-ERS, 2009.

0

20

40

60

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR soybeans

Soybeans

0

5

10

15

20

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR cotton

Cotton

0

20

40

60

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR corn

Corn

0

20

40

60

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR soybeans

Soybeans

0

20

40

60

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR soybeans

Soybeans

0

5

10

15

20

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR cotton

Cotton

0

5

10

15

20

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR cotton

Cotton

0

20

40

60

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR corn

Corn

0

20

40

60

80

1990 1992 1994 1996 1998 2000 2002 2004 2006 2008

Year

Acr

es p

lant

ed (

mill

ion)

Conservation tillage: ≥30% residue Tillage leaving < 30% residue

No-till HR corn

Corn

Environmental Effects

Glyphosate-Resistant Crops

• Substituted for more toxic herbicides

• Exclusive, repeated use reduced effectiveness of glyphosate for control of some weeds

• Expect further increases in weeds resistant to glyphosate if current practices continue

• Managing resistant weeds: a return to environmentally-harmful practices

• Development and implementation of efficient resistance management strategies needed if herbicide resistant crops are to remain an effective weed-management tool

Environmental Effects

Insect-Resistant Crops• If replacing broad-spectrum insecticides, then

favorable effects for beneficial insects may occur• No resistance of economic or agronomic

consequence so far

• Greater use of IR crops with multiple toxins targeting pest should delay the evolution of resistance further

Gene Flow

• No or very limited spatial overlap between GE crops and potentially interbreeding relatives in the United States

• Future concerns depend on what GE crops emerge in market

• Primarily a concern to producers of non-GE varieties of these crops

Environmental Effects

Adequate research has not been conducted on the social effects on GE crops

• Social impacts accompany technological developments

Social Effects

• Social relationships affect technology development

• Structure of seed industry affects farmers’ options

Social Effects

40

45

50

55

60

65

70

75

2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

CR

4 (p

erce

nt)

Corn

Soybean

Share of planted acres on corn and soybean

seeds by largest four firms (CR4)

Source: Stiegert et al. (2009)

Areas in Need of Research

Social Effects

• Non-Adopters- Livestock Producers- Organic Farmers

• Property Rights and Ethical Issues

• Farmer Conflict and Community Stability

Adopters have benefitted from:• Cost-effective weed control• Reduced losses from insect pests• Reduced expenditures on pesticides and fuel• Increased worker safety• Greater flexibility in

farm management• Lower risk of yield variability

Economic Effects

Economic effects on non-GE producers are mixed and poorly understood

• Purchasing decisions of GE producers affect non-GE producers

• No quantitative estimate of economic impact on livestock producers

• Landscape-level effects on pests

• Costs of inadvertent gene flow

• Benefits of segregated markets

Economic Effects

• Stakeholder group needed to document emerging weed-resistance problems and develop cost-effect practices to increase longevity of HR technology

• Infrastructure needed on the water quality effects of GE crops

• Public and private research institutions improve monitoring and assessment capacity to ensure GE technologies contribute to sustainable agriculture

• Increased support for the development of ‘public goods’ traits through collaborative approaches to genetic engineering technology

Recommendations

Thank you. Report is available online atwww.nap.edu.